Stars / Name ______Date ______Pd __

STEP I

Stars have a life cycle. They are probably born from clouds of dust and gas in space. They light up, live their lifetime, then finally die.

Our sun is an example. Today, it shines because its nuclear furnace has plenty of hydrogen fuel. According to theory, most of its nuclear fuel will be used up in about five billion years. The sun will then become much larger. It will become brighter and turn red. For about 100 million years the sun will be a red giant star. When most of the fuel in its outer layers have been used up, it will become about the size of Mars. Its remaining fuel will give off white light. At this time the sun will become a white dwarf. When the rest of its fuel is used up, it will become a black dwarf in our Milky Way Galaxy.

Stars much larger than our sun usually do not become white dwarfs. They may form pulsating stars, called pulsars. They pulse out great amounts of radiation. They may form neutron stars which have great density. They may even end up as black hole stars. Black holes have great gravity. Their own light cannot escape from them. Anything their gravity traps cannot escape. They simply keep growing in size.

NOW: Complete the statements to the right.

STEP III

Find and circle you answers on the grid below. Note: Words can read in any direction.

B L A C K H O L E S

B I D L N E T I H W

A I R O Y R S D T G

E A R U S A D W O N

P R R D B E I A O I

A E T S S L E R U W

C G A U C C T F T O

S R A S L U P H E R

E A O T E N H E R G

R L T N A I G D E R

STEP IV

Now read left to right, row by row, the letters you have not circled for a hidden message about the work sheet topic. Write it here:

______.

STEP II

Write in the missing word to complete the statements below.

  1. ______have great gravity.
  1. For 100 million years the sun will be a ______star.
  1. Larger stars may form ______stars which have great density.
  1. Today the sun shines because its ______furnace has plenty of fuel.
  2. These stars pulse out great amounts of radiation ______.
  1. Black holes simply keep ______in size.
  1. Stars much ______than our sun usually do not become white dwarfs.
  1. Stars are born from ______of dust and gas in space.
  1. Anything that the gravity of a black hole traps cannot ______.
  1. When a red giant uses most of the fuel in its ______layer it will become much smaller.
  1. Stars live their life, and finally ______.
  1. Most of the sun’s nuclear fuel will be ______up in about five billion years.
  1. A red giant star changes into a ______dwarf.
  1. When all the fuel of a star is used up, it will become a black ______.